Method of refining vegetable oils



Aug. 11, 1936. E. M. JAMES METHOD OF REFINING VEGETABLE OILS Filed March 7, 1933 M MW n N W T. T A

Patented Aug. 11, 1936 UNITED STATES PATENT ()FFICE Sharples Specialty Company, Pa., a corporation of Delaware Philadelphia,

Application March 7, 1933, Serial No. 659,918

Claims.

In my co-pending application Serial No. 567,220, filed October 6, 1931, a continuous method of refining vegetable oils was described and claimed. In accordance with the method described in that application, vegetable oil and alkali are continuously fed in carefully proportioned amounts through a continuous high speed mixing device adapted to effect an intimate contact therebetween, and the mixture of oil and soap-stock formed by the reaction in the mixing device is continuously passed from that mixing device through a continuous heater which rapidly raises the mixture to a temperature which facilitates centrifugal separation of the soap-stock from the neutral oil. The mixture is then passed directly from the heater to a battery of centrifugal separators for separating soap-stock from the 011.

Such a method of operation possesses important advantages from the standpoint of avoidance of loss of valuable oil by saponification and entrainment in the soap-stock and it effects considerable economies in time, space and equipment. Purified oil passing from the system, like purified oil obtained by the more conventional gravity settling process, contains, however, a certain amount of impurities in the nature of aqueous alkali solution and soap-stock. These impurities tend to cause a saponification of the purified oil when they are allowed to remain in contact with it for a prolonged length of time and the present invention has as a principal object the removal of these impurities so promptly that deteriorating effects caused by their presence are arrested before substantial damage to the oil has occurred.

To this end, the present invention involves the passage of vegetable oil, purified in accordance with the process described above, promptly through apparatus adapted to effect a continuous washing of the oil with warm water, after its passage from the centrifugal separators. In order to complete the removal of the impurities as promptly as possible, the major portion of the 45 wash water and impurities are then continuously separated from the oil by centrifugal force.

In the preferred embodiment of the invention, the deteriorating influence of any moisture which may remain in the oil after the centrifugal sep- 50 aration of the major portion of the wash water, is also promptly arrested by subjecting the oil to a continuous drying operation.

The attached drawing illustrates, in diagrammatic form, an embodiment of the invention.

Referring to the drawing by reference characters, the numeral l0 indicates a battery of centrifugal separators adapted to effect a continuous centrifugal separation ofsoapstock from neutral oil. As explained in my co-pending application referred to above, the mixture of oil and soap- 5 stock which is subjected to centrifugal separation is formed by a continuous sequence of operations involving continuously mixing the oil with an alkaline solution and thereafter passing the mixture continuously to the centrifuges 10 through a heater adapted to heat the oil and soapstock to a temperature between and 160 F. As pointed out in that application, a preferred process of continuous operation involves limitation of the mixing operation to a period of not 15 more than five minutes, limitation of the continuous heating operation to a period of not more than two minutes and direct passage of the mixture from the heater to the centrifugal separators. The entire contact between the main body of 2 alkali and the oil is thus limited to a period of not greater than approximately eight minutes.

Purified oil discharged from the battery of centrifuges I 0 is passed through a plurality of parallel conduits to a common discharge conduit 5 II. This oil is then fed through apparatus for continously washing and drying it. In the il lustrated embodiment, oil is discharged by conduit I i into a supply tank I! containing a float arm l3. This float arm may be connected to a 30 warning signal ll of any suitable kind adapted to warn the operator of the accumulation of any excess of oil in the tank l2.

Oil is continuously fed from the tank 12 by means of a pump l5 through a conduit Hi to continuous agitating apparatus II. This agitating apparatus may comprise a tank provided with means ill for agitating the 011 during its continuous passage through the agitating tank I! and it may be additionally provided with means for heating the oil during its passage through the tank, such, for example, as a steam coil, as indicated at IS. A supply of water is continuously fed to the tank I! through the conduit 20, the amount of water fed to this tank being carefully proportioned to the volume of oil fed thereto by the pump l5.

In cotton-seed oil refining, most grades of oil can be best washed by the use of a volume of water amounting to approximately 15% of the 50 volume of oil under treatment. Warm water is preferably fed through the conduit 20, and the body of oil and water passing through the tank I! is preferably additionally heated to a temperature between and 210 F. by means 55 of the coil is to facilitate the adequate removal of alkali and other impurities from the oil. Under normal conditions of operation the discharge of the mixture of oil and water from the tank I! is controlled by means of a float 2| which actuates a valve 22. The mixture is fed through a. conduit 23 under the control of this valve 22 to a battery of centrifuges 24 in which water and impurities are continuously separated from the purified oil, the water, alkali and other impurities being discharged at 25 and the purified 011 being passed through a discharge conduit 26 to a float controlled tank 21 from which it is passed to continuous drying apparatus, such, for example, as a continuous vacuum dryer, as indicated at 28. The dried oil is discharged from this drying apparatus into a conduit 29 and fed by the pump 30 to any suitable container 3|. A supplemental storage tank 32 may be provided for use in cases in which it is desired to'feed theoildirectly from the centrifuges 24 to storage. a

The continuous washing and drying operations described above can be'completed within a very short time after the removal of the main body of'the soap-stock from the oil and the entire contact between the oil and any alkali or water used in the refining andwashing processes is limited to the shortperiod involved in the initial mixing, heating and centrifuging operations utilized for the removal of fatty acids and coloring impurities and the.brief additional period required for the continuous water washing and drying operations described above. It will thus be seen that, by the practice of the present invention, it is possible to avoid any prolonged con tact between the oil and any substance tending to cause rapid deterioration thereof. By continuously water washing the oil, it is possible to rapidly remove alkaline impurities tending to cause saponification thereof and by promptly and continuously removing water remaining in the oil after the water washing operation, any deterioration of the oil by reason of prolonged contact with moisture is likewise avoided. The entire water washing and drying operation is preferably limited to a period of not greater than thirty minutes.

Modifications will be obvious to those skilled in the art and I do not therefore wish to be limited except by the scope of the sub-joined claims as interpreted in the light of the generic spirit of my invention.

I claim:

1. The method of refining fatty oils which comprises intimately mixing oil and alkali for not more than five minutes to effect the neutralization of the free fatty acids contained in the oil, promptly thereafter separating the neutral oil within about two minutes thereafter from the soap-stock and other impurities to produce an oil containing only slight traces of residual impurities and continuously passing the neutral oil from said separating step into contact with water, mixing said oil with the water and thereafter promptly separating the neutral oil from promptly passing the neutral oil from said separating step into contact with water, mixing said 011 with the water and thereafter promptly separating the neutral oil from the water and other residual impurities.

3. The method of refining fatty oils which comprises intimately mixing oil and alkali to effect in a single operation the neutralization of the free fatty acids contained in the oil, promptly thereafter separating the neutral oil from the soap-stock and other impurities to produce an oil containing only slight traces of residual impurities and promptly passing the neutral -oil from said separating step into contact with water, mixing said oil with the water, promptly separating the oil from the water and other residual impurities and subjecting the oil to a continuous drying operation to promptly remove residual moisture.

4. The method of continuously refining fatty oils which comprises intimately mixing oil and alkali to effect in a single operation-the neutralization of-the free fatty acids contained in the oil, promptly thereafter separating the neutral oil from the soap-stock and other impurities to produce an oil containing only slight traces of residual impurities and promptly passing the neutral oil from said separating step into contact with water, heating .the mixture of oil and water, mixing said oil with the water and thereafter promptly separating the neutral oil from the water and other residual impurities, the entire operation being performed during the continuous fiow of oil through the system.

5. The method of refining fatty oils which comprises intimately mixing oil and alkali to effect in a single operation the neutralization of the free fatty acids contained in the oil, promptly thereafter centrifugally separating the neutral oil from the soap-stock and other impurities to produce an oil containing only slight traces of residual impurities and promptly passing the neutral oil from said separating step into contact with water, mixing said oil with the water and thereafter promptly separating the neutral oil from the \water and other residual impurities.

6. The method of refining fatty oils which comprises intimately mixing oil and alkali to effect the neutralization of the free fatty acids contained in the oil, promptly thereafter centrifugally separating the neutral oil from the soapstock and other impurities to produce an oil containing only slight traces of residual impurities and promptly passing the neutral oil from said separating step into contact with water, mixing said oil with the water, heating the mixture of oil and water, and thereafter promptly centrifugally separating the neutral oil from the water and other residual impurities, the entire operation being performed during the continuous fiow of oil through the system.

'7. The method of refining fatty oils which comprises intimately mixing oil and alkali to effect the neutralization .of the free fatty acids contained in the oil, promptly thereafter separating the neutral oil from the soap-stock and other impurities to produce an oil containing only slight traces of residual impurities and promptly passing the neutral oil from said separating step into contact with water, mixing said oil with the water, promptly separating'the oil from the water and other residual impurities and subjecting the oil to a continuous drying operation to promptly remove residual moisture, the entire operation being performed during the continuous flow of oil through the system.

8. The method of refining fatty oils which comprises intimately mixing oil and alkali to effeet the neutralization of the free fatty acids contained in the oil, promptly thereafter centrifugally separating the neutral oil from the soapstock and other impurities to produce an oil containing only slight traces of residual impurities and promptly passing the neutral oil from said separating step into contact with water, mixing said oil with the water, promptly separating the oil from the water. and other residual impurities by centrifuging and subjecting the oil to a continuous drying operation to promptly remove residual moisture the entire process being completed within a period of not more than approximately thirty-eight minutes.

9. The method of continuously refining fatty oils which comprises the steps of forming a single admixture of oil with a sufficient proportion of alkali to effect the neutralization of the free fatty acids contained in the oil and the removal of the coloring matter and a substantially complete refining, immediately thereafter separating the neutral oil from the soap-stock and other impurities to produce a substantially refined oil containing only slight traces of residual impurities in a single separating operation, immediately and continuously passing the neutral oil from said separating step into contact with a definitely controlled proportion of water, heatingand agitating the mixture of oil and water to assist the removal of slight residual impurities before any contamination of the oil can take place, immediately separating the oil from the water and other residual impurities and subjecting the oil to a continuous drying operation to effect a prompt removal of residual moisture before deterioration of the oil from contact therewith can result.

10. The method of refining fatty oils which comprises the steps of forming a single admixture of oil with a suflicient proportion of alkali to effect the neutralization of the free fatty acids contained in the oil and the removal of coloring matter and a substantially complete refining, iminedia'tely thereafter centrifugally separating the neutral oil from the soap-stock and other impurities to produce a substantially refined oil containing only slight traces of residual impurities in a single separating operation, said mixing and separating steps being performed within a continuous period of not more than eight minutes,

immediately and continuously passing the neutral oil from said separating step into contact with a definitely controlled proportion of water comprising about 15%, heating and agitating the mixture of oil and water to assist the removal of slight residual impurities before any contamination of the oil can take place, immediately centrifugally separating the oil from the-water and other residual impurities and subjecting the oil to a continuous vacuum drying operation to effeet a prompt removal of residual moisture before deterioration of the oil from contact therewith can result, the steps subsequent to the initial separation of oil from soap-stock consuming time not substantially in excess of thirty minutes.

EDWARD M.' JAMES. 

